package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.db.sql.Order;
import com.hmdp.dto.Result;
import com.hmdp.entity.SeckillVoucher;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.SimpleRedisLock;
import com.hmdp.utils.UserHolder;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.web.bind.annotation.RequestMapping;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.Duration;
import java.time.LocalDateTime;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.*;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    @Resource
    private ISeckillVoucherService seckillVoucherService;

    @Resource
    private RedisIdWorker redisIdWorker;

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private RedissonClient redissonClient;

    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;
    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }

    //利用阻塞队列存订单信息
    //private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024 * 1024);
    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();

    @PostConstruct
    private void init(){
        SECKILL_ORDER_EXECUTOR.submit(new VocherOrderHandler());
    }

    private class VocherOrderHandler implements Runnable {
        String queueName = "stream.orders";
        @Override
        public void run() {
            while (true) {
                try {
                    // 1.获取队列中的订单信息 XREADGROUP GROUP g1 c1 COUNT 1 BLOCK 2000 STREAM stream.orders >
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                            StreamOffset.create(queueName, ReadOffset.lastConsumed())
                    );
                    // 2.判断消息是否获取成功
                    if (list.isEmpty() || list == null) {
                        // 2.1如果获取失败，说明没有消息，继续下一次循环
                        continue;
                    }
                   // 3.解析消息中的订单信息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> value = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(value, new VoucherOrder(), true);
                    // 4.如果获取成功，可以下单
                    handleVocherOrder(voucherOrder);
                    // 5.ACK确认 SACK stream.orders g1 id
                    stringRedisTemplate.opsForStream().acknowledge(queueName,"g1",record.getId());
                } catch (Exception e) {
                    log.error("处理订单异常",e);
                    handlePendingList();
                }
            }
        }

        private void handlePendingList() {
            while (true) {
                try {
                    // 1.获取pending-list中的订单信息 XREADGROUP GROUP g1 c1 COUNT 1 BLOCK 2000 STREAM stream.orders >
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1),
                            StreamOffset.create(queueName, ReadOffset.from("0"))
                    );
                    // 2.判断消息是否获取成功
                    if (list.isEmpty() || list == null) {
                        // 2.1如果获取失败，说明pending-list没有消息，结束循环
                        break;
                    }
                    // 3.解析消息中的订单信息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> value = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(value, new VoucherOrder(), true);
                    // 4.如果获取成功，可以下单
                    handleVocherOrder(voucherOrder);
                    // 5.ACK确认 SACK stream.orders g1 id
                    stringRedisTemplate.opsForStream().acknowledge(queueName,"g1",record.getId());
                } catch (Exception e) {
                    log.error("处理pending-list订单异常",e);
                    try {
                        Thread.sleep(20);
                    } catch (InterruptedException ex) {
                        throw new RuntimeException(ex);
                    }
                }
            }
        }

        private void handleVocherOrder(VoucherOrder voucherOrder) {
            // 1.获取用户
            Long userId = voucherOrder.getUserId();
            // 2.获取锁对象
            RLock lock = redissonClient.getLock("lock::order" + userId);
            // 3.获取锁
            boolean success = lock.tryLock();
            // 4.判断获取锁是否成功
            if (!success){
                //获取锁失败，返回错误信息或重试
               log.error("不允许重复下单！");
            }
            try {
                proxy.createVoucherOrder(voucherOrder);
            } catch (IllegalStateException e) {
                throw new RuntimeException(e);
            } finally {
                //释放锁
                lock.unlock();
            }
        }

    }

    private IVoucherOrderService proxy;

    @Override
    public Result seckillVoucher(Long voucherId) {
        // 1.获取用户id
        Long userId = UserHolder.getUser().getId();
        // 2.获取订单id
        Long orderId = redisIdWorker.nextId("order");
        // 3.执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(), userId.toString(), orderId.toString()
        );
        //2.判断是否为0
        int r = result.intValue();
        //2.1不为0，代表没有购买资格
        if(r != 0){
            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
        }

       /* //2.2为0，有购买资格，把下单信息保存到阻塞队列
        VoucherOrder voucherOrder = new VoucherOrder();
        //2.3订单id
        Long orderId = redisIdWorker.nextId("order");
        //2.4用户id
        voucherOrder.setId(userId);
        //2.5代金券id
        voucherOrder.setVoucherId(voucherId);
        //2.6放入阻塞对队列
        orderTasks.add(voucherOrder);*/

        //3.获取代理对象(事务)
        proxy = (IVoucherOrderService) AopContext.currentProxy();
        //3.返回订单id
        return  Result.ok(orderId);
        }

    //异步秒杀
    @Transactional
    public void createVoucherOrder(VoucherOrder voucherOrder) {
        //5.一人一单
        Long userId = voucherOrder.getUserId();
        //5.1查询订单
        Integer count = query().eq("user_id", userId).eq("voucher_id", voucherOrder.getVoucherId()).count();
        //5.2判断是否存在
        if (count > 0){
            //用户已经购买过了
            log.error("用户已经购买过一次！");
        }
        //5.扣减库存
        boolean success = seckillVoucherService.update()
                .setSql("stock = stock - 1")
                .eq("voucher_id", voucherOrder.getVoucherId())
                .gt("stock", 0)
                .update();
        if (!success){
            //扣减失败
            log.error("库存不足！");
            return;
        }
        //6.创建订单
        save(voucherOrder);
    }

/*    @Override
    public Result seckillVoucher(Long voucherId) {
        //1.查询优惠卷
        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);

        //2.判断秒杀是否开始
        if (voucher.getBeginTime().isAfter(LocalDateTime.now())){
            return Result.fail("秒杀尚未开始！");
        }

        //3.判断秒杀是否已经结束
        if (voucher.getEndTime().isBefore(LocalDateTime.now())){
            return Result.fail("秒杀已经结束！");
        }

        //4.判断库存是否充足
        if (voucher.getStock() < 1){
            return Result.fail("库存不足！");
        }

        //分布式锁
        Long userId = UserHolder.getUser().getId();
        //获取锁对象
        //SimpleRedisLock lock = new SimpleRedisLock(stringRedisTemplate, "order:" + userId);
        RLock lock = redissonClient.getLock("lock::order" + userId);
        //判断获取锁是否成功
        boolean success = lock.tryLock();
        if (!success){
            //获取锁失败，返回错误信息或重试
            return Result.fail("不允许重复下单！");
        }
        try {
            //获取代理对象(事务)
            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
            return proxy.createVoucherOrder(voucherId);
        } catch (IllegalStateException e) {
            throw new RuntimeException(e);
        } finally {
            //释放锁
            lock.unlock();
        }

        //同步锁
        *//*synchronized (userId.toString().intern()) {
            //获取代理对象(事务)
            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
            return proxy.createVoucherOrder(voucherId);
        }*//*

    }*/

/*    @Transactional
    public Result createVoucherOrder(Long voucherId) {
        //5.一人一单
        Long userId = UserHolder.getUser().getId();
        //5.1查询订单
        Integer count = query().eq("user_id", userId).eq("voucher_id", voucherId).count();
        //5.2判断是否存在
        if (count > 0){
            //用户已经购买过了
            return Result.fail("用户已经购买过一次！");
        }
        //5.扣减库存
        boolean success = seckillVoucherService.update()
                .setSql("stock = stock - 1")
                .eq("voucher_id", voucherId)
                .gt("stock", 0)
                .update();
        if (!success){
            //扣减失败
            return Result.fail("库存不足！");
        }
        //6.创建订单
        VoucherOrder voucherOrder = new VoucherOrder();
        //6.1订单id
        Long orderId = redisIdWorker.nextId("order");
        voucherOrder.setId(orderId);
        //6.2用户id
        voucherOrder.setUserId(userId);
        //6.3优惠券id
        voucherOrder.setVoucherId(voucherId);
        //6.4把订单数据保存到数据库中
        save(voucherOrder);
        //7.返回订单
        return Result.ok(orderId);
    }*/
}
